#include <stdio.h>
#include <math.h>

int main()
{
    float money;
    float year;
    float rate;
    float interest;
    scanf("%f %f %f",&money,&year,&rate);
    interest = money * powf(1 + rate , year) - money;
    printf("interest = %.2f\n",interest);

    return 0;
}